ST. LOUIS – There’s a good chance you’ll encounter more motorcyclists on the roads as temperatures continue to climb. You may even see some weaving in and out of traffic.

To get to their intended destinations faster, motorcyclists may consider “lane-splitting.” Perhaps you have even been that motorcyclist in the past.

The American Motorcyclist Association defines “lane-splitting” as “the practice of riding a motorcycle between clearly marked lanes for traffic traveling in the same direction.” The AMA also endorses it, but that doesn’t mean it’s legal just anywhere.

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Motorcyclist or not, when venturing out on the roads, you’ll want to keep state laws in Missouri and Illinois in mind. The legal considerations vary among U.S. states based on where there’s an opportunity to split lanes.

Is it legal for motorcyclists to drive between lanes of traffic in Missouri and Illinois? In shorter terms, is lane splitting legal in both states?


Missouri does not have a state statute that specifically addresses lane-splitting. There is one statute, however, that promotes traffic etiquette for motorcyclists, and it’s been in effect since 2010.

Missouri State Statute 304.015 explains:

Whenever any roadway has been divided into three or more clearly marked lanes for traffic, the following rules in addition to all others consistent herewith shall apply. …

  (1)  A vehicle shall be driven as nearly as practicable entirely within a single lane and shall not be moved from such lane until the driver has first ascertained that such movement can be made with safety

Missouri Statute 304.015

As the bill is written, decisions and risks associated with lane-splitting are in the hands of motorcyclists. The statute advises anyone operating a vehicle to drive as closely as possible within the boundaries of a single lane and to only proceed outside of that lane after they have determined the maneuver can be completed safely.

Short answer: Is it legal in Missouri? Yes, but under the stipulation that motorcyclists consider the situation in which they attempt to split lanes before it happens.


A statute within the Illinois Vehicle Code doesn’t specifically use the term lane splitting, but offers guidance for a practice that comes close to the AMA’s interpretation.

Illinois statute 625 ILCS 5/11-703 within the Illinois Vehicle Code explains:

The driver of a 2 wheeled vehicle may not, in
passing upon the left of any vehicle proceeding in the same direction, pass upon the right of any vehicle proceeding in the same direction unless there is an unobstructed lane of traffic available to permit such passing maneuver safely.

Illinois Statute 625 ILCS 5/11-703 (Illinois Vehicle Code)

Essentially, the motorcyclist (two wheels) is not permitted to maneuver to the left of one vehicle if that move would also be to the right of another vehicle, except in cases where there is a lane completely open between both vehicles without another passerby in the vicinity of that lane.

Short answer: Is it legal in Illinois? No, at least not by the standards of the AMA’s definition of “lane splitting.”

Other considerations

Lane splitting may present different risks in different situations. Some common considerations before lane-splitting legally could be the amount of room, the amount of protection and the speed of travel between cars in any given situation.

This analysis comes after a motorcyclist attempted to split lanes on Interstate 70 in Warren County earlier this month before he crashed and died from his injuries.

If you need legal advice in a road-splitting situation, you should contact an attorney. The information in this article is for general informational purposes only and does not, and is not intended to, constitute legal advice.